Electrical plug connection



Sept. 10, 1929. E. KNICKERBOCKER ELECTRICAL PLUG- CONNECTION Filed July5, 1927 Patented Sept. 10, 1929.

UNITED STATES EARL KNICKERBOCKER, OF MOLINE, KANSAS.

ELECTRICAL PLUG CONNECTION.

Application filed July 5, 1927.

This invention relates to plugs for connecting sources of electricalenergy to electrical current consuming apparatuses and the primaryobject thereof is to provide a plug including a switch which will closethe circuit when the plug is fastened to the socket, the switch being soarranged that the circuit must be broken before the plug can be removedfrom the socket, thus reducing the liability of arcing between thecontacts which tends to burn the terminals.

The novelty of the invention will be clearly understood by reference tothe following description in connection with the accompanying drawingsin which:

Fig. 1 is a perspective view of an iron to which my invention isapplied.

Fig. 2 is an enlarged sectional view through the socket, the plug beingshown partly in section and partly in elevation.

Fig. 3 is a rear elevational view of the plug and socket ininterengagement and Fig. 4 is an end view ofthe same.

The electrical device, containing a heating element, is illustrated asan iron 1, having an upstanding socket 2 to receive a plug 3. Within thesocket 2 are two pins or con tacts 4 and 5 to be received in the socketcontacts 6 and 7 in the plug. One end of the socket 2 is provided with arectangular opening 8. The other diametrically opposite end wall of thesocket 2 is provided with an inverted T-shaped slot 9. The plug 3carries a push-switch, comprising a transversally reciprocatory bar 10having on one end a T-shaped head 11. The plug can be fastened in anyappropriate manner to a conductor or cable 12 supplied with the electrical current from any suitable source. When the switch bar 11 is inthe position shown in Fig. 2, the circuit will be open. The plug may nowbe forced into the socket so that the contacts 4 and 5 are received inthe contacts 6 and 7. At this time the bar can pass through the narrowpart 13 of the slot 9. The end 14 of the bar will be sub stantiallyflush with one edge of the plug 3. When the plug is seated down in thesocket 2, the operator will push the bar 10 tlansversally in the plug sothat the end 14 Serial No. 203,565.

will engage the opening 8 and the head 11 will be received in theenlarged portion 15 of the slot 9. Since the horizontal dimension of thehead 11 is greater than the narrow portion 13 of the slot 9 and sincethe end 14 of the bar engages the opening 8, it will be impossible toaccidentally withdraw the plug since the bar constitutes both a switchoperating element and a fastening means or latching means between theplug and the socket. In other words, when the bar is in the positionshown in Fig. 2, the circuit in the plug is open and when it is in thepositions shown in Figures 3 and 4, the circuit is closed.

From the foregoing it will be apparent that the plug cannot be insertedin the socket 2 with the switch closed, but that the closing must takeplace after the contacts 4, 5, 6 and 7 are in interengagement and thatthe plug cannot be removed until the switch in the plug is opened.Consequently, danger of arcing and burning the contacts 4, 5, 6 and 7will be eliminated. Another advantage is that danger of injury to theper ends of the contacts 4 and 5 and the upper edge of the socket 2.Therefore, if the circuit in the plug is closed before it is put in thesocket, the head on the bar 10 will act as a stop for the full insertionof the plug because the head 11 cannot pass through the slot 13.Consequently, the plug will not touch the short contacts 4 and 5. As aresult the iron cannot be heated until the bar 10 is moved to theposition shown in Fig. 2, at which time the circuit in the plug isbroken. This is an important fea ture because if the contacts 4, 5, 6and 7 could be brought together while the switch in the plug is closed,arcing would take place. The short contacts eliminate t possibility ofthe contacts being brought together while the switch is closed intheplug.

What I claim and desire to secure by Letters-Patent is 1. An electricalplug connection comprising a socket having a slot with an enlargedportion in its edge, a plug, cooperative con tacts in the socket and inthe plug and a switch element carried by the plug having a head movableinto the enlarged portion of the slot to latch the plug "to the socketwhen the switch is closed and movable out of engagement with enlargedportion of the slot when the switch is open.

2. An electrical plugconnectionicomprising a socket having a key-holeshaped slot in one wall thereof, a plug, -cooperating contacts in thesocket and in the plug'anc'l a switch carried by the plug having aheadedreciprocatory bar, the smaller end of which is projectable through anopening in the wall of the socket opposite the slot, the head of the barbeing larger than the narrow part of the key-hole shaped-slot so thatwhen the small end of the bar is in the opening in the socket, the headof the bar will be in the large part of the key-hole shaped slot toprevent withdrawal ofthe plug. 7

3. An electrical plug connection comprising a socket having akey-holeshaped slot in one wall, a plug having contacts adapted to contact withcomplementary contacts in the socket and a switch having a reciprocatorybar provided with a head movable into and out of the enlarged portion ofthe keyhole shaped slot, e i

4. An electrical plug connection comprising a socket and a plug havingco-operating contacts and a reciprocatory latching 'bar carried by theplug for engaging the socket when the switch is on and disengaging thesocket when the switch is off.

In testimony whereof I affix my signature.

EARL KNICKERBOCKER.

